Modern industrial machinery such as manufacturing and processing equipment frequently relies upon very precise coordination and/or control of various aspects of the machinery in order to achieve a desired functionality. However, such machinery must be constructed within certain manufacturing tolerances that limit the achievable precision between the cooperative actions of various components of a complex machine. Also, normal wear and tear on a machine can cause variations from design parameters that can affect the precision of relationships and interactions between different machine components. Another source of uncertainty is the dynamic response of components to loads experienced during operation. Failure to achieve a desired level of coordination between various components can have serious consequences ranging from a loss of quality in the final product to catastrophic failure of the machinery.
In some instances, computerized detection and control systems are employed to achieve and/or maintain a desired level of precision of relative action between different components of an apparatus. The effectiveness of such systems is limited, however, by a number of factors including the ability of the detection systems to accurately and rapidly detect and compare the status or functioning of the relevant components during operation of the machine, thereby precluding the user from determining if the desired accuracy in the operational parameters is achieved.
Often the desired functionality of a machine is achieved by the cooperative actions of related components that include and/or are controlled by co-rotating shafts or other rotating components. For example, rotating shafts may directly drive particular related components or the shaft may include cranks, cams, or eccentric portions that act on other components through connecting hardware. When different co-rotating shafts are driving different cooperating machine components, the co-rotating shafts typically must maintain a particular rotationally-phased relationship with each other. The accuracy of the phased relationship can be critical to proper operation of the overall machine.
It will be appreciated that in large mechanical systems, particularly in applications involving large and/or rapidly changing loads, achieving a high degree of precision in the phase relationship between rotating shafts can be a challenge. While the design of machinery to produce a desired phase relation between components is typically straightforward for the ideal machine, in the real machine the phase relation between components may vary due to a number of factors including, for example, (i) manufacturing tolerances and, in particular, the accumulation of such tolerances; (ii) elasticity in the components under the applied loads, including temperature-related changes in such properties; (iii) changes in dimension and material properties due to temperature variations; and (iv) wear and tear in the equipment over time. Accurately determining the rotational phase between components may be important for machine design, proper set-up, control, and/or detection of problems.
There is a need, therefore, for systems and methods for determining the phase relation between rotating components in mechanical systems.